A Médecins Sans Frontières team was scrambling at the height of the Ebola crisis in West Africa in 2015. They needed to step up their contact tracing of potentially infected victims to stop the chain of Ebola transmission — but they didn’t have reliable geographic information of villages in the Tonkolili district of Sierra Leone.
So they came up with a plan: recruit motorbike taxi drivers with GPS-enabled Android smartphones, install an open-source survey software on their phones, then train them to collect the GPS coordinates of each village in the district.
The result, two weeks later, was a map of 950 villages in Tonkolili. And it came with a bonus: the name and phone number of each village leader and local health care worker, population in the village, number of households, and the location of the closest health facility.